RESUMEN
STUDY OBJECTIVES: To compare the clinical effectiveness of two peripheral nerve block techniques combined with sciatic nerve block: sciatic psoas compartment (SPC) and sciatic femoral 3-in-1 (SF 3-in-1) block. DESIGN: Prospective, randomized study. SETTING: Military medical academy hospital. PATIENTS: Thirty-six ASA physical status I patients, aged 20 to 33 years, undergoing elective knee arthroscopy. INTERVENTIONS: Patients having SPC block (n = 19) or SF 3-in-1 block (n = 17) received 40 mL of a mixture of solution containing 15 mL of 0.5% bupivacaine, 15 mL of 2.0% prilocaine, and 10 mL of 0.9% sodium chloride. In both groups, the sciatic nerve was blocked with 20 mL of the same solution. An intravenous bolus injection of fentanyl 0.1 mg was used if patients complained of pain. MEASUREMENTS AND MAIN RESULTS: None of the patients in the SPC group experienced pain owing to the applied tourniquet during the operation, whereas 7 patients from the SF 3-in-1 group (41.2 %) reported tourniquet pain. All SF 3-in-1 group patients but only 5 patients (26.3 %) in the SPC group required fentanyl during the operation. In addition, 7 patients in the SF 3-in-1 group required second doses of fentanyl. Patient satisfaction was significantly higher in the SPC group than in the SF 3-in-1 block group (P < 0.0001). CONCLUSIONS: Both SPC and SF 3-in-1 provided sufficient anesthetic efficacy for knee arthroscopy. However, SPC may be preferable to SF 3-in-1 block owing to better patient satisfaction and less requirement for opioid analgesics.